diff --git a/CHANGELOG.md b/CHANGELOG.md
index 054b1ad..fca379a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@ Latest
 ------
 
 ### Changes
+* [#56](https://github.com/cleverage/rest-process-bundle/issues/56) Require `symfony/polyfill-php83`, `symfony/polyfill-php84` and `symfony/polyfill-php85` ([cleverage/process-bundle#299](https://github.com/cleverage/process-bundle/issues/299)): the functions of PHP 8.3 to 8.5 can be used while supporting PHP 8.2. Rector targets PHP 8.2 (`withPhpVersion()`, `withPhpSets()` read from `composer.json`) and applies the rules using a newer function when its polyfill is required (no change needed in the current code).
 * [#52](https://github.com/cleverage/rest-process-bundle/issues/52) Give a code to the task ([cleverage/process-bundle#91](https://github.com/cleverage/process-bundle/issues/91)): `rest_request` (`task: rest_request`, with `cleverage/process-bundle` 5.4 or later, referencing it by `service` being deprecated there). The task has its class name as service id; fetching it directly from the service container is deprecated (`container.private`), it will be private in 4.0. The former id `cleverage_rest_process.task.request` is a deprecated alias, removed in 4.0. Update documentation, add tests.
 * [#50](https://github.com/cleverage/rest-process-bundle/issues/50) CI: test the lowest versions allowed by `composer.json` (`--prefer-lowest`, PHP 8.2). Raise `psr/log` to `^2 || ^3`: `cleverage/process-bundle` loggers and the test loggers use the typed `log()` signature, a fatal error with `psr/log` 1.
 * [#48](https://github.com/cleverage/rest-process-bundle/issues/48) `Client::geUri()` (deprecated since v3.2, use `getUri()`) triggers a deprecation at runtime with `trigger_deprecation()` (`symfony/deprecation-contracts`, now required). Add tests.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9a8dfba..23ed8e4 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -40,6 +40,14 @@ make quality
 make tests
 ```
 
+## PHP version
+
+The bundle supports PHP 8.2 and later: do not use a syntax introduced by a later version (typed class constants,
+property hooks, pipe operator...). The functions of PHP 8.3 to 8.5 (`json_validate()`, `array_find()`, `array_any()`,
+`mb_trim()`, `array_first()`...) can be used: they are provided by the required `symfony/polyfill-php83`,
+`symfony/polyfill-php84` and `symfony/polyfill-php85` packages on the older versions. Rector (`make quality`) is
+configured accordingly.
+
 ## Deprecations notices
 
 When a feature should be deprecated, or when you have a breaking change for a future version, please :
diff --git a/composer.json b/composer.json
index f9a13a3..48ee50f 100644
--- a/composer.json
+++ b/composer.json
@@ -59,7 +59,10 @@
         "symfony/http-client": "^6.4 || ^7.4 || ^8",
         "symfony/http-client-contracts": "^3",
         "symfony/http-kernel": "^6.4 || ^7.4 || ^8",
-        "symfony/options-resolver": "^6.4 || ^7.4 || ^8"
+        "symfony/options-resolver": "^6.4 || ^7.4 || ^8",
+        "symfony/polyfill-php83": "^1.33",
+        "symfony/polyfill-php84": "^1.33",
+        "symfony/polyfill-php85": "^1.33"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "*",
diff --git a/rector.php b/rector.php
index 7628528..a601b30 100644
--- a/rector.php
+++ b/rector.php
@@ -3,23 +3,21 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
-use Rector\Set\ValueObject\LevelSetList;
 use Rector\Symfony\Set\SymfonySetList;
 use Rector\ValueObject\PhpVersion;
 
 return RectorConfig::configure()
-    ->withPhpVersion(PhpVersion::PHP_85)
+    ->withPhpVersion(PhpVersion::PHP_82)
     ->withPaths([
         __DIR__.'/src',
         __DIR__.'/tests',
     ])
-    ->withPhpSets(php82: true)
+    ->withPhpSets()
     // here we can define, what prepared sets of rules will be applied
     ->withComposerBased(phpunit: true, symfony: true)
     ->withPreparedSets(deadCode: true, codeQuality: true, symfonyCodeQuality: true)
     ->withAttributesSets(symfony: true)
     ->withSets([
-        LevelSetList::UP_TO_PHP_82,
         SymfonySetList::SYMFONY_CONSTRUCTOR_INJECTION,
     ])
 ;